Electric lamp



A.. ZLLER ELECTRIC LAMP Filed Nov. .10, 1915 Patented daily 2Q, limo.

'- BEI) ZLLEE, 0F CHARLOTTEINB'UR,

ELECTRIC LAMP.

Application tiled November .10, 1916, Serial No. Home, and in Germany November Il, 24.913.

(GRANTED 'UNDER 'THE ERVLSIONS 0F Tm LGT @E MARCH 3, 1321, dl. STAT. L., 1313.)

Incandescent lamps, especially 'metallic filament lamps, have the disadvantage that the inner facesof the glass bulb turn black after a time. This defect is mainly shown by the so called half-wattlamps; these are lamps with a coiled filament glowing in-an linert gas such as nitrogen or the like.

This invention relates to an improvement of the last-mentioned classof lamps. Its main Objectis to arrange a cooling-chamber suitably spacious in comparison with the filament chamber, in such a manner that it cannot be directly struck by the direct rays of the incandescent body. This may be effected, for instance, by a reflecting shield preventing the direct rays from reaching the cooling chamber, but allowing tliehot gases to flow from the filament chamber to the cooling, chamber and back again. The shield, besides, may be used as a carrier for the filament, as-it`is well known. Moreover, it is possible to enlarge the coolingchamber in the horizontal plane, so that n0 rays may get to the cooling-chamber.

The improvement of this invention, in

comparison with the known arrangements consists in the fact that the temperatures of the filament chamber and the cooling chamber are more different from one another than hitherto, in consequence of which the evaporated and thrown-off parts are more intensively cooled and deposited than hitherto.

The main object of this invention is to construct the filament chamber in such a manner that only a few vapours condense on its inner side, or, that the inner sides are only a little covered with the condensed gas.

In the accompanying drawings, wherein correspondingparts are represented by like characters in the various views,

Figure l shows a lamp of low candle power and provided with a small cooling chamber;

Figure 2 shows a lamp of high candle power and provided with a large cooling chamber extending in a vertical plane;

. Referring to the ldrawinglin detail, a is the filament arran ed in t e lamp chamber b; o is the ceo ing-chamber, on the inside of which the gases condense. d is a shield made of metal, black glass or the like and, if desired, it may be provided with a, mirror preventing the radiating heat from oing to the coolingechamber and also acting to deflect the rays ef light in the desired direction and thus it serves as a reector. The shield d lies within the lamp chamber l) and is arranged adjacent the point of communication between the lamp and cooling chambers.

A. better cooling etdect in the coolingchamber of the above-mentioned lamps may also be attained by surrounding the chamber with a cooling ood heat conducting lining of large sur ace. The large surface may be obtained by providing thesaid lin=` ing with cooling ribs or pipes constructed inside or outside the lamp. Preferably also the lamp socket is formed as a cooling-1inmg for the cooling chamber. By this arrangement, as suggested in Fig. l, not only a more intensive cooling and, consequently,

a morerapid condensation of the vapours is eected, but also the bases of the lamp in the glass bulb are kept cool.

According to the present invention. an improved cooling edect is obtained by providing cooling ribs or pipes extending either 1n a. horizontal or in a vertical plane. The cooling chamber of the lamp, however, may also be provided with cooling ribs inside or outside thereof, by means of which the con-` duction of the heat is substantially increased.

Further the outer globemay be surrounded by a strong wirenet or may be made itself of wire-glass. l

It will be understood that I do not limit myself tothe details of construction'iabove set forth, and that many niodications may be made within the scope of my invention.

What I claim, and desire to secure by Letters Patent of the United States, is as follows:

1. In a gas filled metallic filament electric lamp, a closed .globe having a filament chamber, and a metallic filament thereimn cooling chamber, a screen arranged above the filament within the filament chamber and adjacent the point of communication beductivity associated with the cooling cham- 10 tween the lilament'chamber and the cooling ber.

chamber, said screen being so arranged so 2. A gas filled metallic filament electric as to afford ample space for free circulation lamp as claimed in claim l characterized of hot gases from the lame'nt chamber to by the fact that the lamp cap is extended the cooling chamber, whereby the as vadownwardly over the cooling chamber. 15 pors condensedv in the cooling cham er are 1n testimony whereof I aliix my signadeposited on the walls of the latter, and a ture.

metallic jacket of relatively high heat con- ALFRED ZLLER. 

